 Ownership of greenstone was a mania of the Māori, driving them to endure unimaginable hardships to obtain it.The main greenstone source was in the Taramakau and Arahura Rivers on the West Coast, roughly opposite Kaiapoi.Until the Ngāti Wairangi of the West Coast were conquered about the year 1800, the expeditions sent across the ranges by Ngāi Tahu were war-parties, equipped to fight for the greenstone they wanted.